Poration



Sept. 22, 1925. ,554,252

c. z. sMTH IGNITION SYSTEM Original Filed 11, 1920 17 j www/Am M I V TOR W M TToRNEks 'Patented Sept. 22,'1925Q r ,UNITED 'STATES PATENT OFFICE.

CHARLES Z. SMITI-I, OF ALBANI, NEW `YORK, ASSIGNOR T MOTOR IGNITION COR-' PORATION, OF ALBAN'Y, NEW YORK, A CORPORATION OF NEW YOBK.

II IITION SYSTEM.

continiation of application Serial No. 429,845, filed December 11, 1920 This application filed May 4, 1922.

Serial No. 558385. v

To all whom z'tv may cancer-n:

Be it known that I, CHARLES Z. SMrrI-I, a' citizen of the United States, a resident of Albany, in the county of Albany and State of New York, have invented a certain new and useful Improvement in Ignition Systems, of' which the following is a `specification.

The invention has for an object'to pro- 1 Vide an ignition system in the I operation of which the voltage of the secondary cirouit will rise to a proper Value notwithstanding carbonization vor other defects .in the spark plug tending to short cirouit the secondary cirouit, and further to bring about the above result in such manner as to avoid an excessive voltage or other derangement in the secondary cirouit when the, Spark plug is functioning properly.

Another object isto intensify the spark obtainable with the secondary cirouit of an ignition system.

A further object is to accomplish either or both of the above results without giving rise to substantial absorption or 'less of energy. v

The invention also contemplatesa simple and compact form of holder or Cartridge containing devices whereby .the above-men- 3 tioned results may be Secured, and which may readily be inserted in such a secofdary cirouit to aflz'ord proper electrical conneotions to such devices.

Further objects and advantages of the in- 3 vention will be in part obvious and in partspecifically pointed out in the descriptionh'ereinafter contained'which, taken in connection with the accompanying drawngs, discloses 'a preferred embodiment of thein- 4 Vention; such embodiment, however, is to v be considered merely as illustrative of its principle. In the drawings:

Fig. 1 shows diagrammatically a portion of an ignition system dapted to operate according to the inven ion.

Fig. 2 is an end view of a holder or Cartridge containing certain devices which are includedin the cirouit shown inFig.- 1.

Fig. 3 is a central longitudinal section of the hold'er orcartridge shown in Fi .2:

If the secondary cirouit of an igniton sys tem be of suchcharacter that. carbonization `or other defects in the spark plug can resultf in a (high resistance) short cirouit of such secondary cirouit, under such conditions the voltage of the secondary coil will fail to build .up to a proper value, and the 'result 'will be abnormally heavy flow of`current in the primary cirouit, thus causing arcing,` ptting and wearing away of the primary Contacts. a

`On the other hand, if a rise in voltage in the secondary cirouit be insured under all conditions by the use of a plain series gap in connection with a spark plug, the

'voltage of the secondary cirouit may rise the spark plug is functioning properly which might lead to injury to the secondary insulation. 'Referring to Fig. 1-of the drawings, I have shown, more or less conventionally, certain portions of an ignition system,' including a secondary coil 1, which is to be considered merely as any suitable medium for supplying electrical energy through conductors 2 and 3 to the usual s park plug 4 of a gas engine or the like. i

In order to bring about a proper voltage 'in the secondary cirouit, ,both when the spark plug t is functioning properly and when it has been carbonized or otherwise fouled, I interpose between one side of the 'coil' 1 and one electrode'of the spark plug 4 an oseillating circuitcomprsing a condenseror capacity 5 and an additional gap 6, made up of electrodes 7 and 8,' the condensr 5 and gap 6 being in arallel with each other and' both in seres with spark plug 4. Thus, when spark'plug 4 is functioning properly, the potential of' coil 1 will initially be impressed upon the 'electrodes of the spark plug through condenser 5 until such potential is built up t'o a value suflicient to bridge the u electrodes pf. the spark gap. The collapse of the electrostatic field in condenser 5 will then, cause the condenser to discharge through the osciliating cirouit -comprising 4 condenser 5 and the additional or otherwise,

gap 6, with the result that gap 6 will be rendered con ductive, whereby the current from coil 1 may flow through eonductor 2, gap 6, across spark plug 4 and conductor 3 without substantial diminution being caused by the gap 6, since the resistance of the latter has been substantially minimized by means of the discharge from condenser 5( `I prefer to employ a condenser 5 of very small Capacity, for example, in the order of .001 mf., for ignition circuits of ordinary character, in order that the amount of energy absorbed in the condenser in its discharge across the additional gap 6 may be relatively small. Thus, the energy which may be obtained in the discharge across the electrodes o'f spark gap 4 will not be materially decreased. 8

I prefer to include in the oscillating circuit, comprising the condenser 5 and the additional gap 6, an inductance which, in the present embodiment, is in the form of two coils 9 and .10, respectively, which are in series with condenser 5. The inductive effeet of these-coils is preferably so related to the capacity of condenser 5 that sustained 'oscillations are set up' across gap 6 through the condenser and inductances 9 and 10. In

other words, the combined inductance of coils 9 and 10 in micro-henries should be about equal to the capacity of the condenser in micro-farads. Thus, a condition of resonance will obtain in the oscillating circuit and gap 6 will be maintained conductive for a prolonged period of time without substantial losses of energy, whereby the current from coil l may flow across this gap to the spark plug 4 sufliciently long to give proper ignition. As the condenser 5 discharges through inductances 9 and `10, the collapse of their eleetro-magnetic fields will set up a counter-electromotive force which charges' the condenser in the opposite direction, and When the current from coil 1 reverses, the oscillating discharge across gap 6, will keep this gap conductive, and the action of, a spark at plug 4, followed by a spark at the additional gap 6, will be repeated. However, it will benoted that the potential required to bridge spark gap 4 initially is not substantially greater quired if the oscillatng circuit comprising the condenser, inductance and additional gap, were omitted, and therefore the inclusion in the circuit of the features necessary to enable it to operate in accordance with the invention does not give which would be high enough to strain unduly the insulation of the circuit.

Furthermore, in ease the spark plug 4 should be short-circuited, by carbonization the voltage of the coil 1 will still build up to its normal value, since the potential of the coil will be impressed upon than would be re- -d rise to a potential' condenser 5 in the first instance until such potential rises to a value sufficient to bridge theadditional gap 6, and the potential at which this gap ly the same as isrequired to break down the gap at spark plug 4 when the latter is functioning properly. Thus, when spark plug 4 is fouled, no short-circuit results in the secondary, which would result in the occurrence of such heavy current in the primary circuit as to burn the primary Contacts.

The invention may be readily adapted to known ignition systems by means of a structure such as is shown in Figs. 2 and 3. As appears therein, a suitable holder 11, which ordinarly will be of insulating material, is provided with terminals 12 and 13 at its opposite ends, the terminal 12 being illustratedas provided with a binding-nut 14, while terminal 13 holds in position a conne`ctor-clip 15, as by means of a nut 16. If a clip, such as the member 15,. be employed, the holder and the parts contained therein may be readily mounted upon the spark plug, or any other convenient element which forms a part of the secondary circuit, the terminal 12 then being connected "to one of the conductors 2 or 3 of Fig. 1.

In the present instance, metal caps 17 and 18 are pressed over the ends of the insulating holder 11, and terminals 12 and 13 are in the form of screws passing through the caps and clamped thereto by the nuts 19 and 16, respectively' The caps 17 and 18 are sealed in position to provide fluid-tight joints, so as to avoid short circuiting of the parts earried within the holder, due to entrance or oil or the like.

The condenser 5 is contained within the' holder 1, and in the present instance is also of cylindrical shape and substantially cobreaks down is approxmatev axial with holder 11, such condenser nonsisting of the dieleetric 2 0, of glass or the like, and the inner and outer coatings 21 and 22, respectively.

The inductances 9 and 10 are disposed, respectively, between the opposite end surfaees of the condenser and the ends of holder 11, such inductances preferably consisting of coils of resilient wire which are compressed between the caps 17 and 18 and`conducting iscs 23 and 24, respectively, on the ends f the condenser, whereby the coils serve to hold the condenser yieldingly in position as well as to lead current thereto from terminals 12 and 13, respectively.

The electrodes 7 and' 8 of additional gap 6 are also contained within holder 1, and in the present embodiment are in the form of angularly-shaped plates having feet 25 and 26 adapted to be clamped under the heads of terminals 12 and 13 and lying along condenser 5 with their ends spaced to provide the additional gap 6 at the intermediate portion of the hold r. An insulating sleeve 29 may be interposed between the condenser and the 'electrodes 7 and 8 to prevent shortcircuiting. e

I also prefer to provide an opening27 'in' 'common o my co-pending application, Se-` rial No. 429,845, filed December 11 1920, entitled Ignition system.

While the specific embodiment of the invention has been described, it is obviousthat many changes may be made therein without departing from its principle, as' defined in `the following claims:

"I claim: i

1. An igniton system comprising a secondary circuit having a secondary coil, a spark gap, and means for initially impressing the potential of said circuit upon said spark gap, and means associated with saidsecondary circuit for efi'ecting a rise in Voltage of. said secondary coil to substantially normal'voltage in case the resistance of said spark gap is below normal, said means being operative to bring aboutonly a substantially normal rise in voltage of the secondary coil when said spark gap is functioning properly.

2. An igniton system comprising a sec oidar'y circuit having a secondary coil, a

spark gap, and means for initi-ally impressing the potential of said circuit upon said spark gap, and means associated with such secondary circuit for effecting a rise in voltage in the secondary circuit when the voltagerequired to bridge said spark gap is bevoltage when said low normal, commensurate with the rise in spark gap is functioning properly. i

3. The combination with an igniton system comprising a secondary circuit having a secondary coil, and a spark gap, of an additional spark gap associated with said secondary circuit, means for initially impressing the potential of 'said circuit upon "said spark gap, and means associated with such additional spark gap whereby,' when the first-mentioned gap is short-circuited the voltage of said secondary coil will build up to a voltage commensurate' with the rise in voltage when said first-mentio'ned spark gap is functioning properly, (and said additional spark gap will be subjectedtosuch Voltage.

4. An ignition system comprisng a secondary circuit having a secondary coil, a spark gap, and means for initially impress- -ing the potential of said circuit upon said spark gap,` and means associated with said secondary circuit-for efl'ecting a rise in Voltage in the secondary circuit when the Voltage required to bridge said spark gap is below normal, commensurate with the rise in Voltage when said spark gap is functioning properly, said means comprising a condenser in the secondary circuit and an additional spark gap in parallel with said condenser.

5. The combination, with secondary circuit of an igniton system containing a secondary coil and a spark gap, of. an oscillating circuit interposed between one side of the coil and one electrode of the spark gap, .said oscillating circuit comprising a condenser` and an additional gap in parallel and also including an inductance.

6. In combina'tion, a secondary circuit with an igniton system containing a secondary coil and a'spark gap of an oscillating circuit interposed between` one side of the the secondary coil may flow to the spark gap. r

7. In combination, a hollow holder having terminal connections thercon, a condenser and an inductance coil contained' therewithin, said condenser being substantially coaxialwith said coil, and electrodes also within said holder lying along said condenser and coil to make up a spark gap.

8. In combination, a hollow holder hav-l ing terminal connections thereon, a condenser and an inductance coil contained therewithin, said 'condenser being substantially coaxial with said coil, electrodesalso ,within said holder lying along said condenser and coil to make a spark gap, and means for placing said spark gap in parallel with the condenser and coil.`

9. In combination, a hollow holder having terminal connections' thereon, a condenser therewithim and means to hold condenser n proper position comprsng an inductance coil, sad coil bearng against a face of said condenser.

10. In combnaton, a hollow holder havng terminal oonnectons thereon,` a condenser disposed within the central portion of said holder, and inductances located respectively between opposite sur-faces of said condenser and the ends of said holder.

11. In combination, a hollow holder'hav- 'ing terminal connections thereon, a condenser disposed within the' central porti on of said holder, and inductances located respectively between opposite surfaces of said condenser and 'the ends of said holder, said inductances comprising coils of resilient Wire respectively bearing against the opposite surfaces of said condenser, and assisting to maintain the latter in proper position.

12. In combination, a hollow cylindrical holder of insulating material having terminals at its ends,- a condenser disposed withing the central portion of said holder, in-

ductances located respectively between opposite surfaces of said condenser and the ends of said holder, .said inductances comp'ising coils -of resilient wire respectively nterposed between the opposite surfaces of said condenser and the respeetve termnals,

whereby said inductances assist in maintaining the condenser in proper position and afi`ord electrical connection thereto.

13. In combination, a hollow cylindrical holder having terminal connections thereon, a condenser within said holder of cylindrical form and substantially coaxial With the holder, an inductance coil interposed between said condenser and one end of the holder and electrodes interposed between the condenser and the side wall of the holder, said electrodes lying along the condenser and having their ends spaced to provide a gap at the intermediate portion of the cylinder.

In testimony that I claim the foregoing I have hereunto set my hand this 31st day of March, 1922.

' CHARLES Z. SMITH. 

